The traditional and existed bite block generally serve to hold the patient's mouth open and provide an access path for the endoscope inserted into the patient's month to obtaining a visual inspection. At the same time, the patient need to be lying on their right side or left side, i.e. right lateral recumbent position or left lateral recumbent position. However, when the patient is in deep state of unconsciousness during endoscopic inspection using intravenous anesthesia (i.e., painless endoscopy), the upper airway often obstructs due to tongue falling back after induction of anesthesia.
Moreover, some anesthetic drugs would cause a dose-dependent reduction in ventilatory minute volume. On the other hand, some anesthetic drugs would result in airway obstruction and prevent the passage of air. As mentioned above, the patient receiving these anesthetic drugs would have high risk of respiratory related complications such as hypoventilation, hypoxemia and apnea. The patient usually lied down laterally to avoid a blockage in the airway in clinical practice, thus the risks of sedated endoscopic inspection would be decreased. In order to avoid hypoxia due to upper airway obstruction occurring by the tongue falling back after induction of anesthesia in patients, the doctor managed and monitored anesthesia care via the patient's physiologic parameters, such as peripheral oxygen saturation, heart rate, blood pressure, etc., Unfortunately, few patients still suffered from hypoxia, stroke even death during endoscopic inspection.
Existed bite blocks only serve to hold the patient's mouth open and protect the endoscopic device from injury. However, existed bite blocks did not prevent airway obstruction occurring by the tongue falling back. On the other hand, there is a longer distance to nasal cavity and upper respiratory tract from an opening of channel. As a consequence, the patient did not get enough oxygen through the opening of channel. This means that the existed medical bite blocks for endoscopy in clinical practice could not reduce the above mentioned risks and could not solve the above mentioned problems during endoscopic examinations.
Accordingly, how to develop a bite block which could prevent hypoxia due to respiratory inhibition and airway obstruction by the tongue falling back during anesthesia is needed for medical professionals performing endoscopic examinations.